This works fine and dandy for the simple cases, but there are a couple of caveats that should be written down since I haven't seen these mentioned anywhere:

The IE shadow gets the box model wrong: it adds the size of the shadow to the width/height of the element to which it's applied. Beware when floating and applying to elastic layouts.

The IE shadow does not necessarily appear around the element. If you have a div w/ a background-image that is smaller than the div itself, the shadow will be applied to the edge of the background image, not around the outline of the element